P262C: Sensor Reference Voltage G Circuit / Open

What it means

The 5 V reference G output that the engine controller supplies to a group of sensors is open. All sensors fed from this rail will report invalid readings.

At a glance

• Usually lights the check-engine light

How it works

The engine control module supplies a 5-volt reference on circuit G to power or read a group of sensors. P262C means that reference circuit is open, so sensors sharing the G supply can report implausible readings even when those sensors themselves are working. The resulting false inputs can cause rough running, reduced power, or stalling.

Common causes

Most likely first.

1. Open wire on the reference rail
2. Open inside the ECU reference output

Symptoms

• Check-engine light
• Rough running, reduced power, or stalling
• Other sensor-related warning lights may appear

How to diagnose it

1. Record freeze-frame data and related sensor codes, then identify from the vehicle wiring diagram which sensors share reference circuit G.
2. Inspect the reference G wiring, splices, and connectors for breaks, pulled pins, corrosion, or damage.
3. Check the affected sensors' connectors and harness sections for a wire pulled loose or open near the sensor.
4. With the correct wiring diagram, test continuity along reference circuit G from the module connector to its sensor branches.
5. Check for the reference output at the module and at the shared sensor branches using the manufacturer's procedure.
6. If the harness and connections are intact but the module output remains absent, follow the manufacturer's checks to confirm an internal module fault.

Common fixes

• Reconnect a loose sensor plug or repair a pushed-back terminal on circuit G.
• Repair an open reference wire or damaged splice.
• Replace corroded connectors and restore secure terminal contact.
• Repair the module reference output circuit or replace the module only after confirming the external circuit is intact.

Can I keep driving?

If the engine is rough, losing power, or stalling, avoid driving because several sensor readings may be unreliable and the vehicle could stop unexpectedly. If it runs normally, limit driving to a short trip for diagnosis.